Problem: Express this quotient in scientific notation: ${\frac{7.200\times 10^{-7}} {4.0\times 10^{-4}}}$
Explanation: Start by collecting like terms together. $= {\frac{7.200} {4.0}} \times{\frac{10^{-7}} {10^{-4}}}$ Then divide each term separately. When dividing exponents with the same base, subtract their powers. $= 1.80 \times 10^{-7\,-\,-4}$ $= 1.80 \times 10^{-3}$